Malicious RTF — malware analysis report

Static analysis result for SHA-256 540f3d7c62e4572c…

MALICIOUS

RTF

2.78 MB
MD5: 33932b99fdde49d831fb5ce51a414d48 SHA-1: 893a649e43bb728e9af94df2f6e606aa59163d7a SHA-256: 540f3d7c62e4572cf1cb8d191b33e79c87260fc5725e4275a5b402f531b911d2
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains OLE object data and specifically triggers heuristics related to CVE-2017-11882, indicating exploitation of the Equation Editor vulnerability. This vulnerability is known to be used to execute arbitrary code, likely to download and run a secondary payload. The presence of excessive hex data within the OLE object further suggests the hiding of malicious content.

Heuristics 5

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2914KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000052d.bin
231003cea0289e0073d8901bf99d56129a379063f758d01cf68ebfba87be330a		 rtf-objdata-decoded RTF \objdata at offset 0x52D 971757 bytes

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